low bitrates at 1080p

Discussion in 'SJ8 Series' started by Manolis, Mar 3, 2019.

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  1. Manolis

    Manolis New Member

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    Hello,

    I am a new owner of sjcam sj8 pro and would like to raise a concern on the bitrate of recording.
    I had also previous modes of sjcams and I would like to support this company.

    I have seen that the bitrate of recording on 1080p are very low and result in low quality videos.
    at 1080p 60fps it is 18 and at 1080p 30fps it is 12.2.
    These measures are with the video quality set to fine( update: and with h.264 codec used).
    Is there any plan to fix this issue??

    thank you
     
    Last edited: Mar 5, 2019
  2. Michael Dittrich

    Michael Dittrich Member

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    I also think that the bitrates for 1080p are way too low.
    But you have to distinguish between H.264 (aka AVC) and H.265 (aka HEVC).
    H.265 is known to have about the same quality of H.264 at half the bitrate.
    The SJ8 Pro supports H.265.
    Which codec did you use?
     
  3. Michael Dittrich

    Michael Dittrich Member

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  4. Manolis

    Manolis New Member

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    Hello Michael,

    I am recording at h.264 mode.
    The bitrates of recording at this mode are very low for all resolutions except the 4k 60fps at which sj8 pro can reach 100Mbps which is very good.

    My consern is because i know that sj8 pro has ambarella very powerfull processor that could easily reach higher bitrates and this ofcourse would level up this action cam.

    Thanks a lot for the link with the mod sw, but I would like to have a reply from someone from the official site on this aspect. It would be great if next official firmware upgrade could resolve this issue!
     
  5. Manolis

    Manolis New Member

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  6. Michael Dittrich

    Michael Dittrich Member

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    No, I havn't tested it because im mainly use the actioncam as a replacement for carrying an ultrawideangle lens along.
    I think in the respective thread the people using this mod shared their experiences.
    As far as I understud switching back to an official FW should be easy...
     
  7. Michael Dittrich

    Michael Dittrich Member

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    These are the bitrates for 1080p I measured using FW 1.30

    H.265 @ 24fps [KBit/s]
    ======================
    Fine: 8.201
    Standard: 6.750
    Eco: 5.414

    H.264 @ 24 fps [KBit/s]
    =======================
    Fine: 12.400
    Standard: 10.200
    Eco: 8.000

    The resulting samples can be found here:
    https://drive.google.com/open?id=1gUSsNnVoogYAuaTproA3DRQD2RLRzjb1
     
    Last edited: Mar 8, 2019
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  8. Michael Dittrich

    Michael Dittrich Member

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    It is really bad that the bitrate is so small in 1080p (also in the modded FW, as there only 1080p@30fps has a higher bitrate).
    Zooming is not a good idea in 4K but in 1080p it is quiet good (you have the whole range from 12MP to 2MP).
    Lets say up to 3x is vey good and the dynamic range is not bad for the given sensor size.
    Having a higher 1080p bitrate could result in nice timelapses using the digital zoom.

    Here a sample of a timelapse using the flat profile and graded in post:
    https://drive.google.com/open?id=13vQNL7204VjOPl17Q4Z3x8s3Bs1smfQi
    (Here how it looks in Youtube after the upload: )

    Here the ungraded original:
    https://drive.google.com/open?id=157SpOILmGRPQ-AAmllMfbnuiwpqYz-qh
     
  9. Manolis

    Manolis New Member

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    I have read that bitrate for v1.2.8 (official) and the mod firmware mod1 1.2.7(modified) are the the following

    _______________________________________V.1.2.8____ MOD1 V1.2.7

    4K 60FPS - Videop Quality set to ECONOMY..... 51 kBits .......63 kBits
    4K 60FPS - Video Quality set to NORMAL.......... 64 kBits....... 82 kBits
    4K 60 FPS - Video Quality set to FINE ..............105 kBits .....131 kBits

    1080 60FPS - Videop Quality set to ECONOMY 20 kBits .......20.6 kBits
    1080 60FPS - Video Quality set to NORMAL..... 20 kBits....... 20.6 kBits
    1080 60 FPS - Video Quality set to FINE ...........20 kBits ........41 kBits

    So @Michael Dittrich are you sure that at 60fps with 1080p the bitrate isn't increased?
    Have you tried the mod firm? were you hapy with it?

    It is good idea to always check with quality FINE
     
  10. Michael Dittrich

    Michael Dittrich Member

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    I have not checked all the firmware versions, bitrates, codecs and resolutions, as this is too much work.
    I mainly use 24fps when shooting video.
    And I was only interested in 1080p as there the bitrate is insufficient.

    And the versions I tested were
    MOD4 (based on 1.3.0) with even better JPEG quality and center-weighted metering
    MOD4.1 (based on 1.3.0) with adjusted AE metering modes order

    I initially thought all bitrates were changed. But they canged only very few.
    I don't know why they did'n simply double all the 1080p bitrates.

    I think the 4K bitrates are fine. Raising them would result in the requirement of buying faster and more expensive SD cards.
     
    Last edited: Mar 16, 2019
  11. Manolis

    Manolis New Member

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    Yes, totally agree with that!

    By the way is there any official comment on the bitrate quality issue, @Troy could you could comment on that?
     

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